The term lehendakari is a 20th-century neologism. Before the establishment of Standard Basque in the 1970s, it was spelled Euzko Jaurlaritzaren Lendakari. Both lendakari (president) and jaurlaritza (government) are Basque neologisms created by members of the Basque Nationalist Party.

The generic Basque words for "president" and "government" are both lehendakari(a) and presidente(a) for the former, and gobernu(a) for the latter, being presidente(a) and gobernu(a) words loaned from Latin in the absence of an original Basque term for these.

Since the very moment when the noun lehendakari was coined, both lehendakari(a) and presidente(a) have been used as perfect synonyms to refer to the head of any public or private government organ.[2] So lehendakari, in Basque language, is not only the name of the president of the Basque autonomous community,[3] but also the name officially used to refer to the head of the Chartered Community of Navarre,[4] the head of a parliament,[5] the head of a rugby club,[6] the head of a hiring board,[7] the head of a board of directors,[8] etcetera.

On the other hand, the word Lehendakari is commonly used in Spanish, both in and outside the Basque region, to refer exclusively to the Basque president, comparable to the use of Taoiseach as the title of the Irishhead of government in English.

Lehendakaris elected for the PNV have sworn office following a ritual established by Aguirre: next to the Guernica Tree, on a Bible in Basque, using a symbolic formula which reads "before God, prostrated, standing on Basque land, remembering the ancestors, under the Guernica Tree and before you, representatives of the Basque people, I swear...".

Former lehendakari Patxi López used a similar formula in the same place, but also included visible changes to it by suppressing the "before God, prostrated" part and the fact that he sworn on a Basque Statute of Autonomy rather than on a Bible.[9]